This invention pertains to handle blocks for electrical switching devices having an operating handle for manually moving the switch mechanism between ON and OFF conditions. More particularly, the invention pertains to handle blocks for electrical circuit breakers having pivotally operable handles projecting through an opening in the circuit breaker housing.
In certain applications for circuit breakers it is desirable to provide a blocking member for the handle to prevent the handle from being moved from an ON position to an OFF position or vice versa. The blocking member is not to be a lock for the handle, but merely to be a block; i.e. the blocking member may be intentionally removed to permit movement of the handle and operation of the circuit breaker. In prior art devices, the blocking member relies upon engagement thereof within the handle opening in the case for installation to the case. When the handle opening of the circuit breaker case is made particularly small and close fitting to the operating handle for purposes of sealing the housing against the ingress of foreign material, insufficient space is provided to attach a handle block within the handle opening in the case. One prior art handle block is made of sheet metal formed to a three-dimensional collar overlying the handle wherein it is both costly to manufacture and bulky to store when not in use. Still another prior art handle block comprises a multiple piece assembly which is spring biased into notches in sides of the handle opening, which is also costly to manufacture.